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Author Topic: 2019 Elastic Launched Glider  (Read 5015 times)
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Maxout
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« Reply #75 on: February 12, 2019, 11:58:21 AM »

With flapped SO gliders in the 3.9-4.3g range I'm able to get pretty close to 35' with a 4" loop of .060, for what it's worth.

In other news, here's another trimming video. It's intended as instructions for a specific model, but the techniques are the same as for any flapped glider, so I figure it's useful to the broader free flight glider community. And besides, you get to hear one of my sons pitch a temper tantrum while I'm trying to fly an airplane!

https://www.youtube.com/watch?v=MuNag5fH_EI&t=38s
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AC01010
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« Reply #76 on: February 12, 2019, 12:07:06 PM »

With flapped SO gliders in the 3.9-4.3g range I'm able to get pretty close to 35' with a 4" loop of .060, for what it's worth.

I've tried to not stretch my rubber as long because my gliders keep hitting my hand, especially in higher cat 2 ceilings. How could I fix this? I've tried up elevator already, but I'm not sure if I'm doing it right.

I think one loop should be plenty for 40'. I use a loop of 1/8" to get over 50' with an 8 gram model. To be on the safe side you could make two launchers with a double loop on one. Make sure that two loops will work with the launch hook on your model.

Be careful about pushing your model past the point where flutter starts. Once you reach that point adding launch velocity will probably not increase your launch height and it can destroy your model.

Thanks the the help!
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Maxout
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« Reply #77 on: February 12, 2019, 02:15:52 PM »


I've tried to not stretch my rubber as long because my gliders keep hitting my hand, especially in higher cat 2 ceilings. How could I fix this? I've tried up elevator already, but I'm not sure if I'm doing it right.


How long is your loop of rubber? Also, is your wing at negative incidence to the fuselage? My experience is that you want the loop fairly short (3-4") on flappers and that wings mounted at negative incidence are more prone to do weird things like this. Gowen has a variety of workarounds, many of which I've tried rather unsuccessfully. After my debacle at the 2017 Nats with two such planes, I went over a year without touching another flapper before I came back, too a fresh look at it, and decided to do things a different way, and it's worked for me (it also hasn't set any records! Wink ). So now I mount all my wings at 1 degree positive and put some washout in the wingtips to help things along at much more (washout works in reverse at high speeds on flappers).
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Olbill
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« Reply #78 on: February 12, 2019, 04:41:07 PM »

My problem has been the rubber hitting the model as it goes by the launch handle. My solution is the launch handle pictured here. I usually rig the rubber to pull on the curved side but it actually works either way.

Josh's solution makes sense for hand strikes. My solution was more about getting the rubber out of the way of the model.
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Olbill
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« Reply #79 on: February 12, 2019, 04:47:04 PM »

My problem has been the rubber hitting the model as it goes by the launch handle. My solution is the launch handle pictured here. I usually rig the rubber to pull on the curved side but it actually works either way.

Josh's solution makes sense for hand strikes. My solution was more about getting the rubber out of the way of the model.

BTW - this idea originated with John Barker (the one who lived in England) who recently passed away. Here's a photo of his handle.
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AC01010
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« Reply #80 on: February 12, 2019, 07:58:57 PM »


I've tried to not stretch my rubber as long because my gliders keep hitting my hand, especially in higher cat 2 ceilings. How could I fix this? I've tried up elevator already, but I'm not sure if I'm doing it right.


How long is your loop of rubber? Also, is your wing at negative incidence to the fuselage? My experience is that you want the loop fairly short (3-4") on flappers and that wings mounted at negative incidence are more prone to do weird things like this. Gowen has a variety of workarounds, many of which I've tried rather unsuccessfully. After my debacle at the 2017 Nats with two such planes, I went over a year without touching another flapper before I came back, too a fresh look at it, and decided to do things a different way, and it's worked for me (it also hasn't set any records! Wink ). So now I mount all my wings at 1 degree positive and put some washout in the wingtips to help things along at much more (washout works in reverse at high speeds on flappers).

My loop of rubber is about 5" long and my wing is at a neutral incidence to the fuselage (flat wing bottom). I'll try adding a positive incidence as you said.
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Maxout
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« Reply #81 on: March 11, 2019, 09:37:39 AM »

I've had a lot of questions about where to get stuff, so here's a video I made on some of that, plus my dealings with the great folks at Goodwinds who really make a serious effort to serve their customers (unlike our pals at National Balsa who practically slammed the phone when I called asking to order C grain balsa).

https://www.youtube.com/watch?v=hXHQns28mag
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Crtomir
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« Reply #82 on: March 11, 2019, 10:32:17 AM »

I've had a lot of questions about where to get stuff, so here's a video I made on some of that, plus my dealings with the great folks at Goodwinds who really make a serious effort to serve their customers (unlike our pals at National Balsa who practically slammed the phone when I called asking to order C grain balsa).

https://www.youtube.com/watch?v=hXHQns28mag

THANK YOU!!!
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Maxout
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« Reply #83 on: March 18, 2019, 09:47:35 AM »

Much is happening in ELG world this year, and hopefully some of it will eventually show up on youtube, but in the meantime here's some sport flying by yours truly with the Super Protege. This model is a true 20 seconds-from 20 ft airplane, and I've got some video forthcoming to prove it. In the meantime, 30+ seconds from, well, a little higher:
https://www.youtube.com/watch?v=KJ9YR4Il2WU
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Maxout
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« Reply #84 on: March 19, 2019, 09:42:03 AM »

Thought I'd throw out another video I made. How to fix broken gliders. I'm getting a huge number of orders from teams wanting new airplanes because all theirs broke. Yes, some are beyond repair, but hopefully this will help a few learn the lesson that you can fix virtually anything.
https://www.youtube.com/watch?v=rVQvDY2_UM4
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Maxout
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« Reply #85 on: April 26, 2019, 11:20:23 AM »

Perhaps a bit late in the season, but I have done build reviews for most of the available glider kits (the one from Steven's Aero is still in progress). Here the videos showing my findings:
Retro RC: https://www.youtube.com/watch?v=ztZFcciEkIk
Guru: https://www.youtube.com/watch?v=S7Md_mt-htI
Freedom Flight: https://www.youtube.com/watch?v=1hDolLrPDOo

Flying session: https://www.youtube.com/watch?v=lGRu8ZOl3Sc

I found the Guru glider the easiest build by far, but ran into trouble with wing flutter. After taping the wings, this went away, but I've never made it much past 15 seconds in Cat I sites.
The Retro RC model is a pretty reasonable build, puts in similar times to the Guru plane, and doesn't really have bad habits. It's a little higher priced though
The Freedom Flight kit is overengineered by flies quite well. I cannot, however, get any significant camber into the wings. Bottom line: Rohacell is not a material for beginners to mess with. The kits are nice, but that stuff is murder to work with. Also the fuselages are much to underbuilt and that extra 0.5g of weight I ended up needing could have been spend on carbon rods to make the fuselage bulletproof. Also, the wing has nothing to keep it from sliding side to side, making alignment inconsistent. Given the low weight of the model, a movable wing is completely unnecessary.

Of these models, the Guru and Retro RC models will have trouble reaching the ceiling at the Nats. I've tested them outdoors and both fluttered severely when I tried to launch higher than 30'. The wings on the Freedom flight kit are much stiffer. And for comparison I've launched the Proteges to 40' without trouble. You do have to wash out the tips to prevent bunting, but they will go that high if you do your part.
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jdpsloflyer
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« Reply #86 on: April 28, 2019, 07:50:38 PM »

First, second and 4th at Colorado State finals May 27th.  Cumulative scores with bonus' were 60+, 59+ and 40+sec  in ~23ft unobstructed height.  

Flight times for 1st and 2nd were 18-19sec with some 20 sec practice ones.  All gliders were between 4-5 gram weights.  
It seems that whenever the kids added "Official" to their flight, flight time went down a bit.  Nerves I guess.

All planes were the Super Protoege, the best model IMO this year.  

My kids started with scratch built (learning to build) Guru Eng. kits (first kit builds) Protoge (first flapper build) then Super Protoege for competition.  

Congratulations Maxout for a great plane!  The kids are going to Nationals!
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Olbill
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« Reply #87 on: April 29, 2019, 12:54:12 AM »

That's fantastic. Congratulations!
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ceandra
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« Reply #88 on: April 29, 2019, 11:49:17 AM »

JD:

Congrats on a good year! Those are very good times. Your progression through the gliders is certainly a necessary step to performance this year, a lot of learning! We just build glider #12, and are focusing on weight reduction for Nationals.

We'll see you there. We will probably fly early in the day, as I need to get to PA for a wedding that afternoon.

Testing for a 40' ceiling is presenting a bit of a challenge, we have not figured that out yet. Did a little at Round Valley, but focused on AMA planes instead of SO planes.

Chuck
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jdpsloflyer
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« Reply #89 on: April 29, 2019, 02:07:20 PM »

JD:

Congrats on a good year! Those are very good times. Your progression through the gliders is certainly a necessary step to performance this year, a lot of learning! We just build glider #12, and are focusing on weight reduction for Nationals.

We'll see you there. We will probably fly early in the day, as I need to get to PA for a wedding that afternoon.

Testing for a 40' ceiling is presenting a bit of a challenge, we have not figured that out yet. Did a little at Round Valley, but focused on AMA planes instead of SO planes.

Chuck

Chuck,

Thanks!

The kids were getting 20-24 sec in our gym with a 26 ft partition.  If they could launch between the partition and AC (30ft) without hitting anything times were around 24 sec.  I don't know if they can get to 40 ft. We have no venues here that are that high except at CSU in the field house or old gym. I don't know if I can get into them. 

Perhaps we can choose a very calm morning and practice outside at the school.

Does anyone have experience at this?

Jerry
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Maxout
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« Reply #90 on: April 29, 2019, 02:27:19 PM »

I don't know if they can get to 40 ft. We have no venues here that are that high except at CSU in the field house or old gym. I don't know if I can get into them. 

Perhaps we can choose a very calm morning and practice outside at the school.

Does anyone have experience at this?

Jerry

Jerry, congratulations!!!

I trimmed mine outside on calm evenings. That enabled me to go into a 35' site at Southeast Model Show and launch to optimal height without trim changes (there's a video of this on my channel). You'll need to wash out the wingtips a little extra to compensate for the extra speed. The models can and will reach 40' with the right adjustments. Being a little overweight does help in that case in that it makes the launches easier without costing a huge amount in sink rate.
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OZPAF
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« Reply #91 on: April 29, 2019, 08:57:49 PM »

Congratulations on a fine effort from your kids and yourself JD . Also a good result for Josh's Super Protoge.

John
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ceandra
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« Reply #92 on: April 29, 2019, 09:17:24 PM »

Josh: Outdoor "calm evenings" much easier in your neck of the woods than out west. Might happen in June, but not April/May, at least here in ABQ!

Oh well, we'll come up with something. Working on University, as well as State Fair venue, seeing if someone willing to help out these STEM kiddos!

Chuck
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jdpsloflyer
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« Reply #93 on: May 07, 2019, 12:15:29 PM »

Josh: Outdoor "calm evenings" much easier in your neck of the woods than out west. Might happen in June, but not April/May, at least here in ABQ!

Oh well, we'll come up with something. Working on University, as well as State Fair venue, seeing if someone willing to help out these STEM kiddos!

Chuck

Practiced outdoors last Saturday beginning at 8am before the fields were set up for soccer and baseball.
One glider bunted too much to get any height (~24ft). The other reached high enough (guessing here) and transitioned well.  Note to self, there may be thermals forming that can take the gliders away.  A couple of flights had some bubbles of air that lifted the gliders.  I was afraid we were going to lose one.  Luckily they came down within 50yds.  We quit. 

Results were non-bunting Super Protoeges will reach 35-40ft and we need an indoor arena to practice in.

Does anyone know if there will be practice time at Nationals?

Jerry
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ceandra
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« Reply #94 on: May 07, 2019, 12:51:56 PM »

Have not seen any practice time posted yet. The last two years they only allowed testing for 1 hour the morning of the event, and it was a zoo.

We just landed 2 hours of testing at our local university's indoor (football) practice facility. The students are in finals this week, so the facility is unused, and they were happy to support STEM effort! We have two new planes to test for Nationals today in regular gym, and once trimmed out we'll do a 2-hours session in the high ceiling.

It took a lot of phone calls and emails to find a suitable facility, and this one exceeds our needs by a large margin.

Try areas (even some horse arenas), atriums (think large hotels), universities (sports facilities may be open during finals), etc.

Chuck

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« Reply #95 on: May 12, 2019, 11:45:20 PM »

Have not seen any practice time posted yet. The last two years they only allowed testing for 1 hour the morning of the event, and it was a zoo.

We just landed 2 hours of testing at our local university's indoor (football) practice facility. The students are in finals this week, so the facility is unused, and they were happy to support STEM effort! We have two new planes to test for Nationals today in regular gym, and once trimmed out we'll do a 2-hours session in the high ceiling.

It took a lot of phone calls and emails to find a suitable facility, and this one exceeds our needs by a large margin.

Try areas (even some horse arenas), atriums (think large hotels), universities (sports facilities may be open during finals), etc.

Chuck


For these places are they generally free or do you have to rent the space out? I'm worried I won't be able to get the transition properly with a flapped glider at 40' (I've tested outside and been able to get that high though, just haven't been able to get a time with no draft at all)
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ceandra
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« Reply #96 on: May 13, 2019, 02:20:05 PM »

IN most cases we have had to rent gyms, both locally and at Nationals. For a High School gym, expect to pay up to $100 for 2 hours, because they need to pay a custodian to be there while anyone uses the building. We have had various luck with Church gyms, anywhere from free (1-time use) to $20/hour. For high ceiling, these are hard to find. We lucked out, used the STEM educational angle, and got two hours free of charge. This ONLY happened because it was exam week and the athletes were not practicing. Was very surprised to get it at no cost.

For most gyms, expect to have to provide an additional insured certificate. This can be had through AMA, and your kids can get AMA membership free of charge. AMA has a fee for additional insured. The coach will probably need AMA membership as well, about $75/year.

Chuck
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Maxout
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« Reply #97 on: May 17, 2019, 05:49:28 PM »

Hope and I will be at the SO Nats this year. Please come meet up with us during the screenings of Float and at the field house the next day!
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jdpsloflyer
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« Reply #98 on: May 18, 2019, 10:01:25 AM »

Chuck,

We were able to get into the indoor practice field at CSU for 2 hours last week.  It was a productive practice, primarily for launch height and transition.  No outstanding times in this venue because the air was running and creating a lot of turbulence.

The field is half a football field with a 60'+ ceiling (35' at the side) so you can imagine what the air was like with gigantic blowers running.  Fortunately, the kids were able to get in some 35'+ launches with good transitions and glides.  I expect better times in still air at a similar venue, the planes were bouncing all over.

I am grateful that the athletic department let us use the facility, they had been practicing for an NCAA meet earlier.

I am going to Nat's this year, I missed it last year in my home town due to illness.  It will be fun.  If you see an old duffer with a P51 baseball cap I bought from the Air and Space Museum, say Hi.

Jerry
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« Reply #99 on: July 11, 2019, 08:06:56 PM »

2nd place flight at nationals had a total of about 108 seconds, averaging 36 seconds a flight. I used Mr. Gowen's design here. I scaled it down to 30cm wingspan because of the 2019 rules. I also made both stabilizers a little bit larger and I made the wing chord wider by 1/4 inch(?) as well. I had trouble getting the gliders to 40 ft, but one of them was barely able to make it.

Unfortunately, I only have a low quality video of the practice flight :\.
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